1. Field of the Invention
This invention relates to air handling mechanisms and more particularly to an apparatus for optionally delivering inlet air to a centrifugal blower assembly from a plurality of air sources and which may be adapted to treat the inlet air.
2. Description of the Prior Art
In the field of air handling equipment, centrifugal blower assemblies have long been employed for air movement purposes such as ventilation, fume exhaust, and air movement through air conditioning devices such as evaporative coolers, refrigeration units, and the like. Centrifugal blower assemblies have been designed in almost every conceivable size, volumetric output capacity, and pressure range. Also, these blowers have been constructed in down-draft, up-draft, and side draft configurations with many angular variations thereof.
Such centrifugal blower assemblies, regardless of application and the above described variables, are all provided with the same basic components and operate in the same basic manner. In general, centrifugal blower assemblies include a spiral shaped housing having an opposed pair of axial air inlet openings and a centrifugal air outlet opening. Air is drawn into the axial inlets of the blower housing and expelled from the centrifugal outlet thereof by a motor driven impeller mounted axially between the axial air inlet openings.
In air conditioning applications, for which the apparatus of the present invention is ideally suited, such centrifugal blower assemblies are mounted within an enclosing housing so that inlet air to the blower assembly can only be obtained from the ambient air within that housing and delivered externally from that enclosed housing through the centrifugal outlet opening of the blower assembly. The ambient air within the enclosed housing is normally supplied thereto from a single source such as a heating unit, refrigeration unit, or other air treating apparatus as determined by the particular type of air conditioning apparatus. Such air conditioning units may be described as single purpose devices since the air delivered thereby is derived from a single source.
Several multi-purpose air conditioning units have been devised wherein the ambient air within the enclosed housing surrounding the centrifugal blower assembly may be optionally supplied thereto from more than a single source. However, such combination units have heretofore employed one or more centrifugal blower assemblies, complex ducting and air flow control devices, special adapter housings, and the like. Accordingly, such prior art combination devices have been relatively complicated, expensive, and unattractive units. For example, such a prior art multi-purpose air conditioning mechanism may include a central air mixing housing having the centrifugal blower assembly mounted therein and in which damper devices are provided for admitting inlet air to the mixer housing from air treating mechanisms affixed to the mixer housing. Such an air conditioning mechanism may have a conventional existing type of heating device affixed to one side of the mixer housing and a conventional existing type of refrigeration device affixed to the opposite side thereof. Thus, by selective positioning of the damper's devices, inlet air to the mixer housing may be provided through either the heating unit or the refrigeration unit. It may now be seen that by affixing conventional existing air conditioning mechanisms to a special mixer housing a relatively large, complex, and unsightly device results.
It should be noted that such prior art multi-purpose air conditioning units make no provisions for the recirculation of previously treated air and further enclosing structures, ducting, and damper devices would be needed to provide means for accomplishing that function.
One particular prior art multi-purpose air conditioning apparatus is disclosed in U.S. Pat. No. 3,802,493, entitled, "Air Conditioning Apparatus", issued Apr. 9, 1974, to the same inventor. Briefly, that apparatus is a down-draft air delivery mechanism which combines the function of evaporative cooling with other types of air treatment functions. Since this apparatus is a down-draft evaporative cooler, the bottom of the enclosing housing must contain the outlet through which air from the centrifugal blower is delivered and must also have a sump for containing water necessary for the evaporative cooling function. The bottom of the enclosing housing is formed with an upstanding barrier which isolates the centrifugal blower outlet from the sump area and also provides space between the sump and the centrifugal blower outlet for auxiliary air inlets. The upstanding barrier is also employed to carry the centrifugal blower assembly and suitable damper assemblies, which, in conjunction with dampers provided in the auxiliary air inlets, provide the apparatus with the capability of supplying inlet air to the centrifugal blower assembly from either the auxiliary air inlets or from the usual evaporative cooler pads provided on the enclosing housing. By locating various types of air treating devices, such as a heating coil, within the auxiliary air inlets, this particular prior art apparatus may function in a multi-purpose capacity of combining evaporative cooling with various other types of air conditioning functions.
The problems of combining an evaporative cooling function with other types of air conditioning functions in a single apparatus are complex in that the water necessary for the evaporative cooling function must be kept isolated from the other air treating devices and from the centrifugal blower assembly. These problems are further compounded when it is necessary that the single apparatus be configured in a down-draft air delivery mechanism. Thus, by necessity, the apparatus disclosed in the above cited U.S. Patent contains features and elements particularly adapted to solve the problems of that particular type of apparatus.
It may now be seen that the hereinbefore described prior art multi-purpose air conditioning mechanisms have either been relatively large, expensive, and unsightly conglomerations of limited capability or have been devised to solve the particular problems of a specific type of mechanism.
Therefore, the need exists for a new and useful multi-purpose air delivery and treatment apparatus.